#include <iostream>

using namespace std;

// move的方式效率更高
void swap(int & a, int & b){
	int tmp = b;
	b = move(a);
	a = move(tmp);
}

int main(){
	int a = 10;
	int b = 20;
	swap(a, b);
	cout << "a:" << a << ",b:" << b << endl;
	return 0;
}